This invention relates to a device for operating the top end part curving section of an endoscope. A specific aspect of the invention resides in a braking mechanism which is operated under the condition where the direction of the top end part of the endoscope has been determined, and is to be maintained.
In order to observe a portion of a body cavity or to take a picture thereof, the top end part having an observing window of an endoscope is inserted thereinto. In this case, it is necessary to frequently change the direction of the top end part of the endoscope in order to sufficiently observe the portion of the body cavity. For this purpose, in an endoscope of this type, a top end part curving section which is very flexible is provided between the top end part and a flexible pipe coupling the top end part to the manual operating section of the endoscope. The top end part curving section is curved vertically and/or horizontally by strings which are pulled by the manual operation section.
With such a curving section operating mechanism, the portion to be examined is located through observation of the body cavity to take a picture thereof or to perform an operation with forceps or the like. If, in this case, it is possible to maintain the condition of the curving section and accordingly the direction of the top end part of the endoscope as it positioned relative to the affected area, then it is efficient and convenient in conducting subsequent procedures. Accordingly, the curving section operating mechanism is provided with a brake mechanism.
Employed as the brake mechanism in such endoscopes are a pair of rotating knobs curving the which curve section vertically and horizontally, respectively, --; and which is supported in parallel with each other by supporting members. The supporting members are simultaneously clamped and held by applying clamping pressure in the axial directions of the supporting members. Levers are provided for vertically and horizontally operating units, respectively, and these operating units are separately clamped and held by the levers. A braking system of this type has been put to practical use.
In the actual operation of the endoscope for locating the affected part in the body cavity, the vertical and horizontal curving operations are alternately carried out to orientate the top end part of the endoscope as desired. ln this operation, it is necesaary to finely adjust the direction of the top end part vertically and/or horizontally even after the top end part has been directed to the affected part in the body cavity.
In the clamping structure in the axial direction of the supporting members, in the above-described conventional mechanism, the clamping part is in the central region around the supporting shaft of the rotating knob. Therefore the supporting members cannot be clamped and held without increasing the clamping pressures. If the clamping pressures are increased, then it is difficult to finely adjust the direction of the top end part of the endoscope by turning the operating knob under pressure of the braking action. Thus, in the conventional mechanism, it is difficult to design the construction of the frictional surface for applying a suitable brake force and to adjust the clamping pressure.
In the conventional mechanism for separately holding the knobs operating to curve the curving section respectively vertically and horizontally, application of brake forces to the operating knobs to hold them, and release of the applied brake forces must be carried out alternately in locating the affected part in the body cavity and in finely adjusting the direction of the top end part of the endoscope. This is undoubtedly troublesome and prolongs the surgical procedure.